Current human factors evaluation of data collection procedures and monitoring used in the pilot study has already resulted in changes to be implemented in the Full Phase Stroke Data Bank Study. These involve areas of forms, design, formulation of questions, and data collection, feedback and monitoring procedures. Shortly after data collection starts, the reliability and validity of key data items will be assessed, intercenter variability will be measured and criteria of accuracy will be determined and used as objectives in data quality. The reliability assessments will involve intercenter comparisons and test-retest techniques. The validity assessments will involve comparisons of innovative procedures vs. standard procedures. Focus areas include stroke diagnosis, CT Scan and angiography analyses, and functional assessments. Recommendations for improvements in data collection methodology will be made.